A computer network is a collection of interconnected computing devices that exchange data and share resources. In a packet-based network the computing devices communicate data by dividing the data into small blocks called packets. Certain devices within the network, such as routers, maintain routing information that describes routes through the network. In this way, the packets may be individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. Dividing the data into packets enables the source device to resend only those individual packets that may be lost during transmission.
Examples of computer networks include enterprise networks, branch networks, service provider networks, home networks, virtual private networks (VPNs), local area network (LANs), virtual LANs (VLANs) and the like. The computer networks may enable remotely located sources and receivers to share data. In some cases, the computer network may be configured to support multicast traffic, such as Internet Protocol Television (IPTV), desktop conferences, corporate broadcasts, music and video web casts, and other forms of content. As an example, the computer network may utilize protocol independent multicast (PIM) as a multicast routing protocol to control delivery of multicast traffic from sources to receivers for particular multicast groups.
In bidirectional PIM (PIM-BIDIR), all PIM control and data traffic is sent towards a rendezvous point address (RPA) reachable from a rendezvous point link (RPL), and distributed to appropriate destinations. In this way, a source address of multicast traffic may remain unknown to the routers in the network. The routers only need to know the RPA mapped to the multicast group from which the receivers are interested in receiving traffic. In some examples, the RPA may not belong to a real router and may simply be an address reachable from the RPL. In this case, PIM-BIDIR may avoid a single point of failure at the RP. The RPL, however, may be separated into two or more partitions such that receivers and routers in one of the partitions may not be able to receive traffic over the RPL from a source in another of the partitions. Further details of PIM-BIDIR are described in Request for Comments (RFC) 5015, “Bidirectional Protocol Independent Multicast (BIDIR-PIM),” Internet Engineering Task Force, October 2007, the entire contents of which are incorporated herein by reference.